A special room is different from the normal rooms of the randomly-generated dungeon. For example, it might contain a shop or a collection of monsters. They only appear in random rooms-and-corridors levels in the Dungeons of Doom, not in mazes or cavern levels.

This list might be incomplete.

Shops

Shops contain a shopkeeper, an assortment of items, and allow you to buy and sell items. There is at least one guaranteed shop in Minetown. Shops will only be created in rooms with exactly one entrance (and no closets or special features), and are thus usually found at the left or right periphery of the map.

Frequency

(3/DL, DL 2+, not below Medusa, suitable room - note that this always tries to produce shops on levels 2 and 3, although they will only be created if there is a suitable room)

Throne rooms

Throne rooms contain an assortment of monsters, a throne, and a chest. The monsters are always generated hostile.[1] There is a guaranteed throne room in Fort Ludios (if the Fort is generated at all). There are also guaranteed thrones in the Castle and in Vlad's tower; however, the rooms they are located in are not considered throne rooms.

Temples

An altar with a priest tending it is a temple. If the priest and altar are co-aligned with you and your alignment record is good enough, the temple is a sanctuary. If a temple's resident priest dies or is otherwise removed[citation needed] from the room, the temple becomes haunted. Every time you enter a haunted temple, there is 1/5[3] chance of "an enormous ghost" appearing next to you, paralysing you for a three turns, and then acting as an ordinary ghost. A haunted temple cannot be restored.

Known locations of temples

Minetown is guaranteed to have a temple altar, but this level may leave bones and so the altar, the priest or both may not exist. Note: As of 3.6.0 occasionally Minetown will be replaced with Orcish Town. This version has been overrun by orcs, and its temple is desecrated. This new version of Minetown originally appeared in the variant UnNetHack.

What to do in a temple

It is possible to change the alignment of an altar in a temple by sacrificing a monster, especially the right type of unicorn, but doing so will anger the priest. More information is on the page about altars.

What not to do in a temple

When you are BUC testing rings, do not put them on inside the temple. If the ring is a ring of conflict, chances are you will have YASD on your hands. In fact, it is probably just a good idea to use the altar to do this anyway.

If you are read-identifyingscrolls that you have recently BUC tested in the temple, it would be a good idea to read scrolls that are possibly Scrolls of fire away from the priest, preferably in another room, to avoid having the scrolls accidentally damage and anger the priest.

If there is a gas spore in the room, lure it out of the temple before killing it - if you kill it while in the temple and the priest is caught in the explosion, the priest will get angry.
Do not test a drum that might be a drum of earthquake anywhere on the level. If the altar is within line of sight, it may be destroyed, and the priest be made hostile. Even if the altar is not within line of sight, the priest may still be made hostile by a chasm opening underneath him.

Frequency and alignment

One temple is created with probability 1/5 from level 9 on in an ordinary rooms-and-corridors level in the main dungeon, provided it does not already have a shop, a throne room, a leprechaun hall or a zoo.[4] There is an 80% chance the temple is the same alignment as its hosting dungeon branch, the rest of the time it has 1/3 chance of each alignment.[5][6]

Messages

Since NetHack 3.6.0, the following sounds can be heard if a priest is present whose alignment matches that of the altar: [7]

"You hear someone praising <deity>." (only if the priest can speak)

"You hear someone beseeching <deity>." (only if the priest can speak)

"You hear an an animal carcass being offered in sacrifice." (only if you can't see the priest or altar)

"You hear a strident plea for donations." (only if the priest can speak)

The following other messages are related to temples:

"You have a forbidding feeling." (entering, temple desecrated or cross-aligned)

"You have a strange forbidding feeling." (entering, alignment record -4 or lower)

"You experience a sense of peace." (entering, alignment record 20 or higher)

"You experience an unusual sense of peace." (entering, alignment record less than 20)

On levels containing graveyards, undead creatures are less likely to leave corpses[9] (1/9 as likely if killed by you, and 1/3 if otherwise). This includes wraiths, whose corpses are highly desirable. Some players take the trouble to lure wraiths away from graveyard levels before killing them. Note that the Castle is considered a graveyard level.

Anthole

Frequency

(1/8, DL 13+)

Messages

No level sounds.

"You enter an anthole!" (entering)

Barracks

Filled with either soldiers, sergeants, lieutenants or captains, depending on depth. There are guaranteed barracks in the castle and in Fort Ludios. Contains chests or boxes (created on roughly 1/20 of squares).

The occupants will be asleep if nothing has woken them; Fort Ludios soldiers will automatically awaken when you enter the level.

Frequency

(1/4, DL 15+, soldiers not genocided/extinct)

Messages

"You hear blades being honed."

"You hear loud snoring."

"You hear dice being thrown."

"You hear General MacArthur!" (hallucinating)

"You enter a military barracks!" (entering)

"You enter an abandoned barracks." (entering, empty)

Swamp

Swamp rooms occur together: up to 5 rooms on a level may be swamps, with a chequered pattern of pools of water containing sea monsters. Various fungi are generated on some of the land spaces.

You can easily guess the presence of hidden doors in swamps, because of the absence of water pools near the door. Very small swamp rooms can generate just one water pool, easily mistaken for a fountain, so be careful.

Frequency

(1/6, DL 16+)

This room has been known to very rarely appear between Medusa's level and the Castle.

Frequency

Messages

Vaults

Vaults are 2x2 rooms (4x4 including external walls) with gold on each of the empty squares. Tunnels are not generated to them so you will either have to dig to reach them, or fall through a trap door and land inside. Landing inside a vault without a pickaxe to escape with can be remedied by waiting for the guard to escort you outside.

Levels with vaults might contain a room with a square marked "ad aerarium" (Latin: to the treasury) written in the dust. If you search long enough on such a square you will find a hidden door, behind which there may be a teleport trap. If there is a teleport trap, it will take you into the vault (unless you are magic resistant; you can press Control-T to use the trap while standing on it if this is the case). The trap disappears once used; you will have to escape the vault on your own.